Can a bad summer grade prevent an offer from being made?

I have had several interviews so far and a couple went really well. My GPA for the first year put me in the top 20%, however I got a C+ on a summer exam. Obviously, the grade won't count towards my rank until after the Fall semester (which I hope I can get good grades to disguise that bad one). But, I'm afraid this will hurt me if a firm asks for my official transcript before making an offer? Do firms ask for official transcripts before making an offer? Has anyone ever heard of someone losing an offer because of one bad summer grade?

Please advise as I have received quite a few screening interviews and several of them went very, very well. I'm really nervous here....Thanks!

I'm assuming that the OCI interviews you received required you to submit a transcript sometime earlier in the summer. If this is the case, most firms you interview with at callbacks will not ask you for a new transcript, but some will. Those that ask for an updated transcript will do so at your callback interview, prior to offering you a summer position.

I have not heard of someone losing a permanent offer from one bad grade...